Sensitivity Improvements in Uncooled Microbolometer FPAS.

摘要

Raytheon Systems Company has developed a prototype infrared imaging rifle-sight using an uncooled, microbolometer FPA. The high-sensitivity FPA (SBRC-151) used in the Longwavelength Staring Sensor (LWSS) was developed by Raytheon Infrared Center of Excellence (IR COE). The NETD (noise equivalent temperature difference) sensitivity of the camera has been measured at 14 mK with f/1 optics and at 74 mK with an f/2.1 aperture stop. Excellent imagery has been demonstrated with the f/2.1 aperture. The 320 x 240 FPA utilizes a high- yield CMOS readout integrated circuit (ROIC) that achieves high sensitivity, low output nonuniformity, and large scene dynamic range. The ROIC provides multi- level, on-chip nonuniformity correction and on-chip temperature compensation. The FPA has 50 mm x 50 mm pixels and operates at frame rates up to 60 Hz with a single output. The LWSS was characterized by the US Army's NVESD in 1997 using an earlier version of the SBRC-151 FPA. The NVESD measurements validated the Raytheon NETD data. The NVESD evaluation also demonstrated outstanding MRT and spatial noise characteristics. The VOX microbolometer detectors are produced at the Raytheon IR COE facility in Santa Barbara, CA using an advanced dry-etch fabrication process. In addition to the LWSS project, the IR COE has initiated production of the microbolometer FPAs (AE-189) for commercial applications. Over 600 FPAs have been produced on this project, and data is presented for the first 250 FPAs that have been packaged and tested. The pixel operability of the production radiometer FPAs (AE-189) is typically greater than 99.9%.